我需要通過 jquery 或 vanilla javascript 以編程方式更改模式的寬度。這是我所擁有的：<div class="modal fade" id="modal-popup" tabindex="-1" role="dialog" aria-labelledby="myModalLabel">  <div class="modal-dialog modal-lg" role="document" id="modal_dialog">    <div class="modal-content">      <div class="modal-header">                <h3 class="modal-title pull-left" id="action_title">My Title</h3>        <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">×</span></button>      </div>      <div class="modal-body text-center">My Body</div>      <div class="modal-footer">        <button type="button" class="btn btn-default" data-dismiss="modal">Close Window</button>      </div>    </div>  </div></div>我似乎無法使用它：function popUpModal(){     $('#modal-popup').modal('show');   $('.modal-content').css('width','99%');     console.log('it is firing!');  }我在這里錯過了什么嗎？